There is already a known practice of installing separation nipples on filler pipes which are connected to a vent line of a tank and, on the other hand, have outlet lines leading to a fuel vapour filter, in particular, an activated carbon filter. Fuel vapour escaping from the tank can be passed through an installation of this kind to the activated carbon filter, wherein, on the flow path of the vapour, the separation nipple ensures as complete separation of the liquid fuel as possible from the gas carried onwards in the direction of the activated carbon filter. The liquid fuel separated out can be discharged into the filler pipe via an opening of the separation nipple and can flow back into the tank via said pipe.
Another known practice when opening a tank flap on pressurized tank systems is to abruptly discharge any possible excess pressure in the tank system by opening a solenoid valve. “Instant venting” of this kind is intended to avoid fuel spray escaping due to the excess pressure in the tank. However, instant venting leads to such a high pulse-type volume flow that inadequate liquid separation may lead to liquid fuel being transferred to the activated carbon filter and, in turn, may lead to a fuel spray from the filler head.